U.S. patent application number 09/940977 was filed with the patent office on 2002-10-24 for periphyton filtration pre-and post-treatment system and method.
Invention is credited to Jensen, Kyle R..
Application Number | 20020153301 09/940977 |
Document ID | / |
Family ID | 26962937 |
Filed Date | 2002-10-24 |
United States Patent
Application |
20020153301 |
Kind Code |
A1 |
Jensen, Kyle R. |
October 24, 2002 |
Periphyton filtration pre-and post-treatment system and method
Abstract
Periphyton filtration is a known method for performing
bioremediation of polluted water, removing nutrients from the
influent on which the attached algae thrive. The present system
improves upon this method by adding a strong oxidizer to the
influent, and, in some cases, to the effluent, to make organically
bound nutrients available to a target culture of periphyton or
aquatic plants to reduce the population of undesirable
microinvertebrates, to make organically bound nutrients available
to the periphyton, and to reduce the level of toxic compounds. A
particular embodiment comprises ozonating the water. A pesticide
may be added to control insect populations.
Inventors: |
Jensen, Kyle R.; (Apopka,
FL) |
Correspondence
Address: |
Jacqueline E. Hartt
Allen, Dyer, Doppelt, Milbrath & Gilchrist, P.A.
255 South Orange Avenue, Suite 1401
P.O. Box 3791
Orlando
FL
32802-3791
US
|
Family ID: |
26962937 |
Appl. No.: |
09/940977 |
Filed: |
August 28, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60285001 |
Apr 19, 2001 |
|
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|
Current U.S.
Class: |
210/602 ;
210/760 |
Current CPC
Class: |
C02F 2303/04 20130101;
C02F 3/327 20130101; C02F 2201/78 20130101; C02F 1/32 20130101;
Y02W 10/18 20150501; Y02W 10/10 20150501; C02F 2303/18 20130101;
Y02W 10/37 20150501; C02F 1/50 20130101; C02F 3/32 20130101; C02F
1/78 20130101 |
Class at
Publication: |
210/602 ;
210/760 |
International
Class: |
C02F 001/78; C02F
003/32 |
Claims
What is claimed is:
1. A method of treating water comprising the steps of: exposing
water desired to be treated to ozone in sufficient quantityto
reduce a concentration of undesired microorganisms therein; and
flowing the water over a colony of attached algae to remove
undesired matter therefrom.
2. The method recited in claim 1, wherein the water-exposing step
comprises the steps of injecting ozone into at least one of a
mixing chamber and a body of water, pumping the water to be treated
into the mixing chamber, and mixing the water to be treated with
the injected ozone.
3. The method recited in claim 1, further comprising the step,
prior to the water-exposing step, of generating ozone by at least
one of exposing air to ultraviolet radiation and creating a corona
discharge.
4. The method recited in claim 1, further comprising the step of
exposing the water to be treated to at least one of ultraviolet
radiation and acoustic energy.
5. The method recited in claim 1, wherein the water-exposing step
comprises pumping the water into a bottom end of a tube, injecting
ozone adjacent the bottom end of the tube, and permitting the water
and the ozone to mix while rising toward a top end of the tube.
6. The method recited in claim 1, further comprising the step of
treating the water with ozone following the water-flowing step.
7. The method recited in claim 1, further comprising the step of
passing the water through an activated carbon filter following the
water-flowing step.
8. The method recited in claim 1, further comprising the step of
adding a pesticide to the algal colony for controlling insects, the
pesticide selected from a group consisting of an insecticide, a
pyrethroid, or a natural pyrethrum.
9. The method recited in claim 8, further comprising the step of
adding a pesticide to the algal colony for controlling insects, the
pesticide comprising bacillus therengensus isralioans.
10. The method recited in claim 9, further comprising the step of
culturing bacillus therengensus isralioans, and wherein the
pesticide-adding step comprises delivering a substantiall y
continuous supply of bacillus therengensus isralioans to an inlet
of the algal colony.
11. The method recited in claim 1, further comprising the steps of:
extracting the water to be treated from a body of water prior to
the exposing step; and returning the treated water the to body of
water following the water-flowing step.
12. The method recited in claim 1, wherein the ozone-exposing step
comprises covering a body of water and injecting ozone into the
body of water.
13. The method recited in claim 1, wherein the ozone-exposing step
comprises: pumping water out of a body of water into a supply pipe;
injecting ozone into the supply pipe; and directing the water to an
inlet end of the algal colony.
14. The method recited in claim 13, wherein the ozone-injecting
step comprises injecting ozone at a plurality of injection
locations along the supply pipe.
15. The method recited in claim 1, further comprising the step,
following the water-flowing step, of repeating the ozone-exposing
step and the water-flowing step by recirculating the water emerging
from the algal colony.
16. The method recited in claim 1, further comprising the steps,
following the water-flowing step, of harvesting the algal colony,
adding a pesticide to the harvested algae, exposing the mixed algae
and pesticide to sunlight for achieving detoxification, and using
the detoxified mixed algae and pesticide to form a base for another
algal colony.
17. The method recited in claim 16, wherein the pesticide comprises
one or more pesticides selected from a group consisting of natural
pyrethrum, natural pepper, garlic, elder, and lemon sage.
18. The method recited in claim 1, wherein the colony is attached
to a base, and further comprising the steps, following the
water-flowing step, of harvesting the algal colony, adding a
pesticide to the colony base, and detoxifying the base.
19. The method recited in claim 18, wherein the pesticide is
selected from a group consisting of a synthetic pyrethroid and a
natural pyrethrum.
20. A system for treating water comprising: means for exposing
water desired to be treated to ozone in sufficient quantity to
reduce a concentration of undesired microorganisms therein and to
liberate available nutrients therefrom; a colony of attached algae
for removing undesired matter from the ozone-exposed water; and
means for directing the ozone-exposed water from the water-exposing
means to the algal colony.
21. The system recited in claim 20, wherein the water-exposing
means comprises a mixing chamber, means for injecting ozone into
the mixing chamber, a pump for pumping the water to be treated into
the mixing chamber, and a mixer for mixing the water to be treated
with the injected ozone.
22. The system recited in claim 20, further comprising means for
generating ozone comprising at least one of means for exposing air
to ultraviolet radiation and means for creating a corona
discharge.
23. The system recited in claim 20, further comprising means for
exposing the water to be treated to at least one of ultraviolet
radiation and acoustic energy.
24. The system recited in claim 20, further comprising: a tube
having a bottom end and a top end; a pump for pumping the water
into the tube bottom end and upward toward the top end; means for
injecting ozone adjacent the tube bottom end of the tube, for
permitting the water and the ozone to mix while being pumped toward
a top end of the tube.
25. The system recited in claim 20, further comprising means for
treating the water with ozone downstream of the algal colony.
26. The system recited in claim 20, further comprising the step of
passing the water through an activated carbon filter following the
water-flowing step.
27. The system recited in claim 20, further comprising means for
adding a pesticide to the algal colony for controlling insects, the
pesticide selected from a group consisting of an insecticide, a
pyrethroid, or a natural pyrethrum.
28. The system recited in claim 20, further comprising means for
adding a pesticide to the algal colony for controlling insects, the
pesticide comprising bacillus therengensus isralioans.
29. The system recited in claim 28, further comprising means of
culturing bacillus therengensus isralioans, and wherein the
pesticide-adding means comprises means for delivering a
substantially continuous supply of bacillus therengensus isralioans
to an inlet of the algal colony.
30. The system recited in claim 20, further comprising: means for
extracting the water to be treated from a body of water; and means
for returning the treated water the to body of water downstream of
the algal colony.
31. The system recited in claim 20, wherein the ozone-exposing
means comprises a cover over a body of water and means for
injecting ozone into the body of water.
32. The system recited in claim 20, wherein the ozone-exposing
means comprises: a supply pipe having an inlet end and an outlet
end; a pump positioned to extract water out of a body of water into
the supply pipe inlet end and to pump the extracted water to an
inlet end of the algal colony; and means for injecting ozone into
the supply pipe.
33. The system recited in claim 20, further comprising means for
redirecting water from an outlet end of the algal colony to the
ozone-exposing means for recirculating the water emerging from the
algal colony.
34. The system recited in claim 20, further comprising means for
harvesting the algal colony following exposure to water to be
treated and means for adding a pesticide to the harvested
algae.
35. The system recited in claim 34, wherein the pesticide comprises
one or more pesticides selected from a group consisting of natural
pyrethrum, natural pepper, garlic, elder, and lemon sage.
36. The system recited in claim 20, further comprising a base to
which the algal colony is attached, and further comprising means
for harvesting the algal colony, means for adding a pesticide to
the colony base, and means for detoxifying the base.
37. The system recited in claim 36, wherein the pesticide is
selected from a group consisting of a synthetic pyrethroid and a
natural pyrethrum.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to provisional application
No. 60/285,001, filed Apr. 19, 2001, "Periphyton Filtration
Pretreatment System and Method."
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to systems and method for
improving water quality, and, more particularly, to such systems
and methods for bioremediating water with an attached algal colony,
and, most particularly, to treating water against undesired toxins,
microorganisms, and other water-borne pollutants in concert with an
attached algal colony.
[0004] 2. Description of Related Art
[0005] Algae comprise a group of plants, existing in approximately
18,000 different species, whose primary nutrients include carbon,
nitrogen, and phosphorus, as well as a suite of micronutrients
essential to plant growth.
[0006] The removal of contaminants from wastewater and ground water
has become an important problem in restoring ecological balance to
polluted areas. It is known that some algal species are capable of
absorbing heavy metals into their cell walls, thus reducing their
toxic effects on the environment. Algae can also take up nutrients
and micronutrients that may be present in overabundance, such as
phosphorus, potassium, nitrogen, iron, aluminum, and calcium, and
can thus be utilized to remediate an ecosystem. Such remediation
can occur when water flows over stationary algae, also absorbing
carbon dioxide and releasing oxygen in the process as a result of
respiration and photosynthesis. Further, the water passing over the
PF experiences an increase in pH owing to the removal of carbon.
The filtration can occur through adsorption, absorption, physical
trapping, and other more complex means.
[0007] A system used to effect this uptake is known as a periphyton
filter, the periphyton comprising a culture of a family of fresh,
brackish, and/or salt-water aquatic plants known as attached
microalgae. Unlike such organisms as free-floating plankton,
benthos or attached algae is stationary community of epiphytes that
will grow on a wide variety of surfaces. When occurring in the path
of flowing water, the stationary algae remove nutrients and other
compounds from the passing water, while absorbing CO.sub.2 and
releasing O.sub.2 as a result of respiration and photosynthesis.
Once a colony is established, roots or holdfasts cover the culture
surface. If the plant bodies are harvested, leaving the roots
behind, the nutrients and other pollutants contained in the plant
bodies are removed from the water, causing a natural filtration
effect.
[0008] A further advantage to this technique is that the enriched
algae can be harvested and used as fish or animal feed, which
serves to return the nutrients to the food chain.
[0009] Periphyton filters (PF) have the potential for use in a
variety of applications. For example, the turf can be used to
replace biological or bacteriological filters in aquaria. As
mentioned, natural periphyton can be used to remove nutrients and
other contaminants from polluted waters. In addition, by harvesting
the algal mass, various processes can be used to produce a biomass
energy source such as methane or ethanol, fertilizer, a human or
animal food additive or supplement, cosmetics, or
pharmaceuticals.
[0010] The high productivity of the algae in a fibrous form has
also yielded uses in the paper and paper products industry, as the
harvested algae are stronger and easier to process than wood fiber.
This capability has resulted in a sustainable method of managing
human impact on aquatic ecosystems.
[0011] Periphyton filters behave differently in water with varying
location, speciation, chemical characteristics, and other
parameters. Experience in situ has in some cases resulted in weak
or poor productivity owing to low concentrations of available
nutrients. It has been shown that if a fraction of the primary
nutrients are not available, then the periphyton filters struggle
to develop the critical mass necessary to invoke a substantial
precipitation and physical trapping capability and concurrent
filtration characteristics. In particular, the presence of
microinvertebrates and their eggs can compromise the success of a
periphyton filtration system by consuming desirable periphyton and
by eating the root or holdfast of the algal filament.
[0012] Toxic cyanobacteria pose a particularly formidable set of
filtration challenges in that the toxins are very persistent in the
environment and can exist both inside and outside the algal cell.
It is known to treat toxin-containing water with ozone because of
its strong oxidizing effect when mixed in water; however, the
nutrients in ozonated water become available and are reconsumed by
the toxic algae.
[0013] Studies in algal turf production are known in the art. Algal
turf techniques have been disclosed in Adey's U.S. Pat. No.
4,333,263, and the present inventor's U.S. Pat. Nos. 5,131,820,
5,527,456, 5,573,669, 5,591,341, 5,846,423, and 5,985,147, the
disclosures of which are incorporated herein by reference.
SUMMARY OF THE INVENTION
[0014] It is therefore an object of the present invention to
provide a system and method for pretreating and/or post-treating
water in concert with a periphyton filtration bed.
[0015] It is another object to provide such a system and method for
reducing a population of undesirable microinvertebrates in a
periphyton filtration bed.
[0016] It is an additional object to provide such a system and
method for reducing or eliminating toxins from inflow water as well
as a toxicity level of harvested algal mass.
[0017] These objects and others are attained with the system and
method of the present invention. The system comprises means for
adding a strong oxidizer to the influent, and, in some cases, to
the effluent. A particular embodiment comprises ozonating the
water.
[0018] The method of treating water comprises the steps of exposing
water desired to be treated to ozone in sufficient quantity to
reduce a concentration of undesired microorganisms therein and
flowing the water over a colony of attached algae to remove
undesired matter therefrom, such as, but not intended to be limited
to, nutrients.
[0019] The features that characterize the invention, both as to
organization and method of operation, together with further objects
and advantages thereof, will be better understood from the
following description used in conjunction with the accompanying
drawing. It is to be expressly understood that the drawing is for
the purpose of illustration and description and is not intended as
a definition of the limits of the invention. These and other
objects attained, and advantages offered, by the present invention
will become more fully apparent as the description that now follows
is read in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0020] FIG. 1 is a schematic illustration of a first embodiment of
the invention.
[0021] FIG. 2 is a schematic illustration of a second embodiment of
the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] A description of the preferred embodiments of the present
invention will now be presented with reference to FIGS. 1 and
2.
[0023] It is known to use ozone to treat water because of the
properties of the unstable O.sub.3 molecule, which is a strong
oxidizer. Ozone is typically generated, for example, by ultraviolet
radiation or corona discharge. Since ozone is a gas, it must be
dissolved or broken into small bubbles to optimize contact with the
target microorganisms in the influent and, in some cases, the
effluent. An optimal residence time should be achieved in the water
to be treated to maximize particle contact. This may be achieved,
for example, with a mixing chamber or a mixing pump.
[0024] If the location of the periphyton filter is at some distance
from the water to be treated, mixing may occur, for example,
downstream and generally adjacent a supply pump or pipe entrance,
with a single or multiple static mixers agitating the water/ozone
combination. The residence time is then equal to the travel time to
the periphyton filter, which can be tested for sufficiency of
contact time. In addition, further static mixers and ozone
injection points may be positioned along the pathway to the
periphyton filter to increase effectiveness and efficiency.
[0025] In an alternate embodiment a covered pond may be used, such
a pond cover having an ozone destruct port at the highest location
to catch ozone prior to escaping into the atmosphere. A subsurface
"well-style" tank may be used to increase contact time, such a tank
having a high-pressure ozone injection at its bottom for optimal
dispersion of ozone into the water column.
[0026] The present invention provides the following benefits:
[0027] Ozone breaks up planktonic algae, bacteria, and other
organically bound particles in lake water, thereby making nutrients
available for use and concurrent growth of the periphyton.
[0028] After the nutrients are available and removed by the
periphyton, the water can be returned to the water body from which
it came, or to another water body, in a state that will limit the
ability of toxic algae to regrow, thereby effecting
remediation.
[0029] Ozone destroys certain toxic compounds found in
cyanobacteria (blue-green algae) recently found to be dangerous to
humans and other animals. These toxic compounds, as well as
nontoxic compounds, are then available to be taken up by
filamentous algae grown for industrial use, such as in the paper
products industry
[0030] Ozone destroys both microinvertebrates and their eggs, which
often settle, hatch, and grow as they consume desirable periphyton,
thus reducing the effectiveness of filtration.
[0031] Other devices to be used alone or in conjunction with ozone
to enhance performance are plasma sparkers and ultraviolet light
treatment systems, such as are known in the art.
[0032] Two embodiments of the present invention are illustrated
schematically in FIGS. 1 and 2. In the first embodiment (FIG. 1) of
the system 10 water is shown being taken in from deep water 11,
shallow water 12, or a tributary 13 byway of pipes 14 and pumps
15-17, respectively. An ozone generator 18 provides ozone to an
ozone injection apparatus 19 so that the water desired to be
treated can be contacted with ozone in chamber 20. Alternately, as
mentioned above, a submersible plasma sparker may be used. Ozonated
water is carried via transfer piping 21 to a distribution manifold
22, which distributes the water to the inlet end 23 of a periphyton
bed 24, which is tilted to permit the water to flow downward to the
outlet end 25. The treated water is then collected into a transfer
pipe system 26, and is then either returned to a waterway 27 or
transferred to a drinking water treatment system 28 of ground water
aquifers 29.
[0033] In the second embodiment (FIG. 2) of the system 30,
inflowing water 31 is pumped into ozone distribution piping 32,
into which is also injected ozone from an ozone generator 33. Prior
to exposure to ozone, the water may be exposed to at least one of
ultraviolet radiation and acoustic energy 43. Following passage
through an ozone injection diffuser 34, the water proceeds via
transfer piping 35 into multiple ozone contact chambers 36. Three
are shown here, but this is not intended as a limitation. When
fully ozonated, the water exits via discharge piping 37.
[0034] In either of the above-described embodiments, an additional
step may be taken of adding a pesticide to the algal colony for
controlling insects. The pesticide may be selected, for example,
from a group consisting of an insecticide, a pyrethroid, or a
natural pyrethrum, although these are not intended as
limitations.
[0035] In a particular embodiment, the pesticide may comprise
bacillus therengensus isralioans (BTI). A further element of either
of the systems 10, 30, shown in FIG. 1, comprises a BTI culturing
system 40, wherein BTI is substantially continuously cultured, or
cultured as needed, and a continuous drip of BTI is provided via
line 41 leading to drip hose 42 adjacent the inlet 23 of the
periphyton bed 24.
[0036] As an additional or alternative embodiment, further systems
and methods are envisioned for detoxifying one or more elements of
the system 10, 30. As an example (FIG. 1), the algal colony 24 may
be harvested by means known in the art from its base 44, and a
pesticide P may be added to the harvested algae to form a mixture
24'. This mixture 24' is exposed to sunlight or other means to
provide detoxification and then ground to form a mulch 24". Such a
mulch may then be used atop the base 44 to form a subsequent algal
colony 24. The pesticide may be selected from a group consisting of
natural pyrethrum, natural pepper, garlic, elder, and lemon sage,
although these are not intended as limitations.
[0037] Further, the algal colony 24 may be harvested by means known
in the art, and pesticide P may be added to the base 44 wherein
water is not flowing, and allowed to detoxify the base 44.
Following sufficient time for detoxification, an agonist may be
added, such as an alkaline solution, to detoxify the pesticide
prior to restarting water flow over the algal colony 24. In this
case, the pesticide may comprise at least one of a synthetic
pyrethroid or a natural pyrethrum.
[0038] It may be appreciated by one skilled in the art that
additional embodiments may be contemplated, including alternate
methods of introducing ozone and the use of alternate oxidizing
agents to the treatment water.
[0039] In the foregoing description, certain terms have been used
for brevity, clarity, and understanding, but no unnecessary
limitations are to be implied therefrom beyond the requirements of
the prior art, because such words are used for description purposes
herein and are intended to be broadly construed. Moreover, the
embodiments of the apparatus illustrated and described herein are
by way of example, and the scope of the invention is not limited to
the exact details of construction.
* * * * *